Apparatus for casting scroll member and method of manufacturing scroll member

ABSTRACT

An apparatus for casting a scroll member of a compressor has a first die and a second die. The first die includes a molding surface for molding a base plate of the scroll member. The second die includes a molding surface for molding a scroll wall of the scroll member. The first and second dies define a cavity for casting the scroll member. The first die also includes a first die-member and a second die-member. The second die-member forms a portion of the scroll member, which extends in a direction substantially perpendicular to a direction in which the first and second dies separate from each other.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to an apparatus for casting ascroll member for use in a compressor and a method of manufacturing ascroll member.

[0002] One of compressors used in a refrigerant circuit of a vehicle isa scroll type. The scroll type compressor generally accommodates a fixedscroll member and a movable scroll member in its housing. The fixedscroll member includes a base plate and a scroll wall, while the movablescroll member includes a base plate and a scroll wall. The scroll wallsof the fixed and movable scroll members are engaged with each other.

[0003] Compression chambers are defined between the scroll walls. Thecompression chambers radially inwardly move from the peripheral side ofthe scroll walls toward the center of the scroll walls by orbiting themovable scroll member with respect to the central axis of the fixedscroll member, thus gradually compressing gas introduced from anoutside.

[0004] In such a structure mentioned above, as the compression chambersmove, the volumes of the compression chambers reduce, thus compressingrefrigerant gas. Therefore, ensuring sealing performance around thecompression chambers is important.

[0005] The movable and fixed scroll members are manufactured bydie-casting, which is one of moldings. As shown in FIGS. 3A and 3B, whenthe movable scroll member is cast in a mold, a casting apparatus 55provides a cope 43 and a drag 33 on its center. The cope 43 is a die forcasting a scroll wall of a scroll member 50, while the drag 33 is a diefor casting a base plate of the scroll member 50. The cope 43 and thedrag 33 define a cavity 36 for casting by fitting the cope 43 to thedrag 33. A molten metal is filled in the cavity 36 between the cope 43and the drag 33, and is cooled. The cast scroll member 50 is taken offout of the cope 43 and the drag 33 after the molten metal solidifies.Besides, as a matter of convenience, the scroll member 50 is indicatedby hatching in FIGS. 3A and 3B.

[0006] When the scroll member 50 is taken off out of the cope 43 and thedrag 33, extruding plungers 45 provided in the cope 43 push the end 50 aof the scroll wall and extrude the scroll wall synchronously withseparating the cope 43 from the drag 33. Additionally, extrudingplungers 35 provided in the drag 33 extrude the base plate of themovable scroll member.

[0007] When the scroll member 50 is taken off by the above-mentionedextruding plungers 35, 45, the scroll member 50 is die-cast with theextruding plungers 35, 45 being movably inserted in plunger holes 34,44, which are formed in the drag 33 and the cope 43, respectively.Therefore, incorrect positioning, abrasion and deformation of theextruding plungers 35, 45 cause the shape of the ends of the extrudingplungers 35, 45 to be diverse, and cause the length of the extrudingplungers 35, 45 to be unequal. Consequently, after casting, rough marksdue to the extruding plungers 35, 45 remain on the end 50 a of thescroll wall of the scroll member 50. Namely, when the extruding plungers45 protrude from the molding surface of the cope 43, recesses are formedon the end 50 a of the scroll wall. When the extruding plungers 45recede from the molding surface of the cope 43, protrusions are formedon the end 50 a of the scroll wall. Also, when the scroll member 50 istaken off, the extruding plungers 45 push the thin end 50 a of thescroll wall. Thereby, the scroll wall slightly deforms.

[0008] Due to such recess, protrusion and deformation, when the fixedand movable scroll members define the compression chambers, gaps betweenthe end 50 a of the scroll wall and the facing surface of the end 50 abased on the recess and the protrusion exceed a permissible range, andanother gaps are also defined between the scroll walls. Thereby, therefrigerant gas undesirably leaks. Accordingly, to ensure the sealingperformance around the compression chambers, the end 50 a of the scrollwall of the scroll member 50 and the surface of the scroll wall arerequired to be uniform by machining. Thereby, the process ofmanufacturing the scroll member 50 increases.

SUMMARY OF THE INVENTION

[0009] The present invention addresses the above-mentioned problems byimproving a die for casting a scroll member

[0010] According to the present invention, an apparatus for casting ascroll member of a compressor has a first die and a second die. Thefirst die includes a molding surface for molding a base plate of thescroll member. The second die includes a molding surface for molding ascroll wall of the scroll member. The first and second dies define acavity for casting the scroll member. The first die also includes afirst die-member and a second die-member. The second die-member forms aportion of the scroll member, which extends in a direction substantiallyperpendicular to a direction in which the first and second dies separatefrom each other.

[0011] The present invention also provides a method of manufacturing ascroll member, including a base plate and a scroll wall, by a die havinga first part including a molding surface for the scroll wall, a secondpart including a molding surface for the base plate, and a third partincluding a molding surface to form a protrusion of the scroll member,which extends in a direction substantially perpendicular to a directionin which the first and second parts separate from each other. The methodincludes casting the scroll member in the die, separating the first partfrom the second and third parts while the third part engages with theprotrusion, disengaging the third part from the protrusion, andseparating the scroll member from the second part.

[0012] Other aspects and advantages of the invention will becomeapparent from the following description, taken in conjunction with theaccompanying drawings, illustrating by way of example the principles ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The features of the present invention that are believed to benovel are set forth with particularity in the appended claims. Theinvention together with objects and advantages thereof, may best beunderstood by reference to the following description of the presentlypreferred embodiments together with the accompanying drawings in which:

[0014]FIG. 1A is a schematic cross-sectional view of an apparatus forcasting a scroll member of a compressor in a state of fitting a cope toa drag according to an embodiment of the present invention;

[0015]FIG. 1B is a schematic cross-sectional view of an apparatus forcasting a scroll member of a compressor in a state of separating a copefrom a drag according to the embodiment of the present invention;

[0016]FIG. 1C is a schematic cross-sectional view of an apparatus forcasting a scroll member of a compressor in a state of extruding a scrollmember from a cope according to the embodiment of the present invention;

[0017]FIG. 2A is a top plan view of a cope according to the embodimentof the present invention;

[0018]FIG. 2B is a cross-sectional view taken along the line 1-1 in FIG.2A;

[0019]FIG. 2C is an enlarged partial cross-sectional view of FIG. 2B;

[0020]FIG. 3A is a schematic cross-sectional view of an apparatus forcasting a scroll member of a compressor in a state of fitting a cope toa drag according to a prior art; and

[0021]FIG. 3B is a schematic cross-sectional view of an apparatus forcasting a scroll member of a compressor in a state of separating a copefrom a drag according to the prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] An embodiment of the present invention will now be described withreference to FIGS. 1A through 2C. A casting apparatus 25 shown in FIG.1A is used for casting a scroll member 20 for use in a scroll typecompressor. The scroll member 20 described in the present embodiment isa movable scroll member.

[0023] The casting apparatus 25 includes a fixed installation seat 1 atits lower side, and the fixed installation seat 1 provides a drag 3 as afirst part including a molding surface for casting a scroll wall of thescroll member 20 and a molding surface for casting the surface of a baseplate of the scroll member adjacent to the scroll wall. The castingapparatus 25 also includes a movable installation seat 11 at its upperside, and the movable installation seat 11 connects with a cylinderactuator or another reciprocating actuator as a driving apparatus, whichis not shown, for operating the movable installation seat 11. Also, themovable installation seat 11 provides a cope 13 as a die including amolding surface for casting the base plate of the scroll member 20through a stay 12.

[0024] Thereby, the movable installation seat 11 operatively moves upand down by the driving apparatus, so that the cope 13 can approach andleave from the drag 3. Also, the cope 13 forms a plurality of plungerholes 14, and the lower ends of the plunger holes 14 extend to a cavity6, which is defined by the cope 13 and the drag 3. Extruding plungers 15each extend through the plunger holes 14. One ends of the extrudingplungers 15 are secured to an extruding plate 16, which is positionedbetween the movable installation seat 11 and the cope 13. The one endsof the extruding plungers 15 recede from and protrude into the cavity 6by moving the extruding plate 16 up and down, respectively. Theextruding plate 16 moves up and down by operating a cylinder actuator 19or another reciprocating actuator as a driving apparatus

[0025] As shown in FIGS. 2A through 2C, the scroll member 20manufactured by the casting apparatus 25 is constituted of a base plate21 and a scroll wall 22. The base plate 21 provides a boss 32 on theside opposite to the scroll wall 22. Besides, the plunger holes 14 areformed in the cope 13, and the extruding plungers 15 extend the plungerholes 14 through. The plunger holes 14 and the extruding plungers 15 arenot shown.

[0026] The cope 13, which is the die including the molding surface forcasting the base plate 21, includes a first molding surface 31 a formolding the base plate 21. The first molding surface 31 a forms adisk-shaped cavity, which provides a plurality of recesses 37 a (threerecesses in the present embodiment) in equiangular positions on itsouter periphery. The recesses 37 a are trapeziform in shape, as seenfrom the upper side of the cope 13. The recesses 37 a extend in adirection B, which is perpendicular to a direction in which the cope 13and the drag 3 separate from each other or perpendicular to a directionA. The direction A is a vertical direction in the present embodiment.

[0027] The cope 13 also includes a second molding surface 32 a forcasting the boss 32. The second molding surface 32 a forms a cylindricalcavity, which also provides a plurality of trapeziform recesses 38 a(three recesses in the present embodiment) in equiangular positions onits outer periphery, as well as the recesses 37 a. Protrusions 37, 38are formed in the recesses 37 a, 38 a by casting, respectively.

[0028] The cope 13 includes a main die 13 a as a first die-member and asecond part and a plurality of sub dies 13 b as a second die-member anda third part (three in the present embodiment). The main die 13 a, whichdoes not includes the recesses 37 a, 38 a, operates in the direction A.The sub dies 13 b, which includes the recesses 37 a, 38 a, operate inthe direction B perpendicular to the direction A and in a radialdirection with respect to the central axis of the scroll member 20.

[0029] Meanwhile, the drag 3, which is the die including the moldingsurface for casting the scroll wall 22 of the scroll member 20, includesa third molding surface 22 a for molding the scroll wall 22. The thirdmolding surface 22 a forms a scroll-shaped cavity. The cavity 6, whichforms the scroll member 20, is defined by fitting the cope 13 to thedrag 3.

[0030] In the above-described casting apparatus 25, the cavity 6provides drafts θ in various portions so as to separate the scrollmember 20 from the dies smoothly. As shown in FIG. 2, the second moldingsurface 32 a of the cope 13 provides drafts θ on surfaces for castingthe inner and outer circumferential walls of the boss 32. Also, thethird molding surface 22 a of the drag 3 provides drafts θ on surfacesfor casting the inner and outer circumferential walls of the scroll wall22. The recesses 37 a, 38 a of the sub dies 13 b provide drafts θ on itsupper and lower surfaces and both sides, respectively. The inclinationsof the drafts θ are determined based on difficulty in separating thescroll member 20 from the dies and a required leave for machining aftercasting.

[0031] In FIG. 1, the sub dies 13 b each connect with cylinder actuatorsor other reciprocating actuators, which are not shown, for operating thesub dies 13 b, and the cylinder actuators or other reciprocatingactuators are arranged on the movable installation seat 11. As thecylinder actuators or other reciprocating actuators each reciprocate,the sub dies 13 b each move in the respective directions B. Namely, thecylinder actuators or other reciprocating actuators for operating thesub dies 13 b are arranged so as to reciprocate in the respectivedirections B perpendicular to the direction A.

[0032] The operation of the casting apparatus 25 constructed above willnow be described. As shown in FIG. 1A, the cope 13 is formed by fittingthe sub dies 13 b to the main die 13 a.

[0033] As the driving apparatus operates, the cope 13 with the movableinstallation seat 11 moves downwardly. Thereby, the cope 13 fits ontothe drag 3, thus defining the cavity 6. Heated molten metal passesthrough a gate, which is formed through the drag 3, and the molten metalis forced into the cavity 6 including the recesses 37 a, 38 a byoperating a plunger for injecting the molten metal. The gate and theplunger are not shown. Meanwhile, the end of the extruding plungers 15extend to the bottom openings of the plunger holes 14, and close theplunger holes 14 to define the cavity 6

[0034] The cope 13 and the drag 3 are cooled by cooling water flowingthrough a cooling pipe, which extends in the cope 13 and the drag 3.Thereby, the molten metal injected into the cavity 6 is efficientlycooled and solidified. In a practical manufacturing process, the moltenmetal is cooled and solidified for about a minute.

[0035] As shown in FIG. 1B, the movable installation seat 11 movesupwardly after the molten metal solidifies, and the cope 13 leaves fromthe drag 3, thus starting separating the scroll member 20 from the dies.Meanwhile, since the cylinder actuators or other reciprocatingactuators, which are not shown, for operating the sub dies 13 b arearranged on the movable installation seat 11 and connect with the subdies 13 b, the sub dies 13 b integrally move upwardly with the movableinstallation seat 11. Also, since the sub dies 13 b each engage with theprotrusions 37, 38 formed in the recesses 37 a, 38 a, the base plate 21is lifted up from the drag 3 by moving the cope 13 including the subdies 13 b upwardly. The base plate 21 is easily separated from the drag3 due to the drafts θ of the scroll wall 22.

[0036] As shown in FIG. 1C, the sub dies 13 b moves in the direction Bperpendicular to the direction A and in the radial direction withrespect to the central axis of the scroll member 20, thus separating thesub dies 13 b from the protrusions 37, 38.

[0037] Meanwhile, the cylinder actuator 19 or other reciprocatingactuator operates, and the extruding plungers 15 protrude. Thereby, thebase plate 21 is force out, and leaves from the main die 13 a.

[0038] Since a robot arm 39 extends to a space between the cope 13 andthe drag 3 preceded the separation of the base plate 21 from the maindie 13 a, the robot arm 39 receives the scroll member 20, and finallycarries the scroll member 20 to a next process.

[0039] In the scroll member 20 manufactured as described above, the end20 a of the scroll wall 22 does not provide any recesses and protrusionsas those in the conventional casting apparatus 55. The base plate 21provides recesses and protrusions on a surface opposite to the scrollwall 22. However, the surface opposite to the scroll wall 22 may bemachined, and the recesses and protrusions may disappear. Even if therecesses and protrusions are left as it is, the condition of the surfacedoes not affect the operation of the scroll member 20 in a state thatthe scroll member 20 is assembled to a compressor. Additionally, uponseparating the scroll member 20 from the dies, the extruding plungers 15push the thick flat base plate 21. Therefore, the scroll member 20hardly deforms. If the protrusions 37, 38 are used for assembling thescroll member 20, or are available in operating the scroll member 20,the protrusions 37, 38 may be left. Basically, the protrusions 37, 38are removed by machining.

[0040] The following advantageous effects are obtained from the presentembodiment.

[0041] (1) According to the casting apparatus 25 described above, theend 20 a of the scroll wall 22 of the scroll member 20 does not provideany recesses, any protrusions and any deformations as those by aplurality of the extruding plungers 45 in the conventional castingapparatus 55, and the surface of the end 20 a is flat, thereby reducingor cutting a process for machining the end 20 a and the wall surface ofthe scroll wall 22 of the scroll member 20. Accordingly, time andprocess of manufacturing may be reduced as compared with conventionaltime and process of manufacturing.

[0042] (2) Since the end 20 a of the scroll wall 22 of the scroll member20 provides the drafts θ, the scroll member 20 is easily separated fromthe dies. Therefore, molded surface, so-called a mill scale, whichperforms relatively high durability and abrasion resistance, remainswithout any recesses, any protrusions and any deformations, and is usedas it is.

[0043] The embodiment described above may be modified into the followingexamples.

[0044] In the embodiment described above, the scroll member 20 isseparated from the dies in order of the scroll wall 22, protrusions 37,38, and the base plate 21. However, the order of the separation is notlimited to it. For example, the scroll member 20, which is separatedfrom the dies in order of the scroll wall 22, the base plate 21, andprotrusions 37, 38, is also applied. In such a state, in case the subdies 13 b do not integrally move upwardly with the movable installationseat 11, an additional driving apparatus for moving the sub dies 13 bupwardly is required in addition to the cylinder actuators or otherreciprocating actuators for moving the sub dies 13 b in the respectivedirections B.

[0045] The number of the divided pieces of the cope 13 and the shape ofthe cope 13 are not limited to the embodiment described above. Nothindering the main die 13 a and the sub dies 13 b, which constitute thecope 13, from separating from each other, any structure may be applied.

[0046] In the embodiment described above, the cope 13 and the drag 3 arevertically disposed. However, the cope 13 and the drag 3 may be disposedhorizontally.

[0047] In the embodiment described above, the driving apparatus foroperating the cope 13 is the cylinder actuator or other reciprocatingactuator. However, the driving apparatus is not limited to it. Forexample, a robot arm may be substituted for the cylinder actuator orother reciprocating actuator.

[0048] In the embodiment described above, the scroll member is used in acompressor for an air conditioner of a vehicle. However, the scrollmember may be used in another compressor other than the compressor forthe air conditioner of the vehicle as far as the compressor is a scrolltype.

[0049] According to the present invention, since the end of the scrollwall of the scroll member cast by the casting apparatus ensures a flatend surface, the time and process for machining the end surface of thescroll wall is reduced or cut.

[0050] Therefore, the present examples and embodiments are to beconsidered as illustrative and not restrictive and the invention is notto be limited to the details given herein but may be modified within thescope of the appended claims.

What is claimed is:
 1. An apparatus for casting a scroll member of acompressor, the apparatus comprising: a first die including a moldingsurface for molding a base plate of the scroll member; a second dieincluding a molding surface for molding a scroll wall of the scrollmember, the first and second dies defining a cavity for casting thescroll member; and wherein the first die comprises a first die-memberand a second die-member, the second die-member forms a portion of thescroll member, which extends in a direction substantially perpendicularto a direction in which the first and second dies separate from eachother.
 2. The apparatus for casting the scroll member of the compressoraccording to claim 1, wherein the first die-member operates in thedirection in which the first and second dies separate from each other,and the second die-member operates in a direction in which the portionextends.
 3. The apparatus for casting the scroll member of thecompressor according to claim 1, wherein the portion is a protrusion. 4.The apparatus for casting the scroll member of the compressor accordingto claim 1, wherein the number of the second die-member is three ormore.
 5. The apparatus for casting the scroll member of the compressoraccording to claim 4, wherein the number of the second die-member isthree.
 6. The apparatus for casting the scroll member of the compressoraccording to claim 1, wherein a driving apparatus for operating thefirst die-member is a reciprocating actuator.
 7. The apparatus forcasting the scroll member of the compressor according to claim 6,wherein a driving apparatus for operating the first die-member is acylinder actuator.
 8. An apparatus for casting a scroll member of acompressor, the apparatus comprising: a first die including a moldingsurface for molding a base plate of the scroll member; a second dieincluding a molding surface for molding a scroll wall of the scrollmember and a molding surface for molding the surface of the base plate,the first and second dies defining a cavity for casting the scrollmember; and wherein the first die comprises a first die-member and asecond die-member, the second die-member forms a portion of the scrollmember, which extends in a direction substantially in parallel with themolding surface for molding the surface of the base plate.
 9. Theapparatus for casting the scroll member of the compressor according toclaim 8, wherein the first die-member operates in the directionperpendicular to the molding surface for molding the surface of the baseplate, and the second die-member operates in a direction in which theportion extends.
 10. A method of manufacturing a scroll member,including a base plate and a scroll wall, by a die having a first partincluding a molding surface for the scroll wall, a second part includinga molding surface for the base plate, and a third part including amolding surface to form a protrusion of the scroll member, which extendsin a direction substantially perpendicular to a direction in which thefirst and second parts separate from each other, the method comprisingthe steps of: casting the scroll member in the die; separating the firstpart from the second and third parts while the third part engages withthe protrusion; disengaging the third part from the protrusion; andseparating the scroll member from the second part.
 11. The method ofmanufacturing the scroll member according to claim 11, furthercomprising the step of removing the protrusions.
 12. A cast scrollmember product made by the method of claim 11.